Traffic signal timer



R. A. REID 235.29?

TRAFFI G S I GNAL TIMER Original'i Filed rm. '15, 1936 2 Sheets-Sheet 1 Inventor:

by Min/ His At torney.

March 25, 19410 R 2,236,297

TRAFFIC SIGNAL TIMER Original Filed 062.. 15, 1936 2 Sheets-Sheet 2 lnventor: Ralph A. Rei.

Patented Mar. 25, 1941 PATENT OFFICE TRAFFIC SIGNAL TIMER Ralph A. Reid, Nahant, Mass, assignor to General Electric Company, a corporation of New York Application October 15, 1936, Serial No. 105,684 Renewed June 7, 1940 4 Claims.

My invention relates to signal controllers, and more particularly to trafiic signal controllers commonly referred to as traflic signal timers One object of my invention is to provide an improved trafiic signal timer which is simple in construction, reliable in operation and cap ble of performing respectively the several functions required of apparatus of this type.

Another object of my invention is to provide an improved indicating means for the cycle length setting of the traffic signal timer.

Another object of my invention is to provide an improved. circuit controller drum for traffic signal timers.

For a better understanding of my invention, together with other and further objects thereof, reference is had to the following description, taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

The term timer or traflic signal timer is herein used to indicate a complete controller for one or more sets of traffic signals. It includes a driving mechanism and a circuit controller operated thereby for controlling the circuits for the dilferent signals used during a complete trafiic signal cycle.

In the accompanying drawings; Fig. 1 is a front view of my improved trafiic signal timer; Fig. 2 is a perspective view of the mechanism of the timer; Fig. 3 is a front perspective of the improved circuit controller drum; Fig. 4 is a side viewof one of the cams used in the drum of Fig.

- 3; Fig. 5 is a section of the drum controller contact block illustrating an assembled and an exploded view of a set of contacts respectively, 'which are operated by cams of the controller drum; and Fig. 6 is a schematic diagram of the circuit connections between the elements of the timer and the signals.

Referring to the drawings in detail, Fig. 1 illustrates the front panel 9 of my improved timer. This panel is provided with an opening II! in which a disk H is mounted having thereon means for adjusting the signal periods. The dial ll, shown in greater detail in Fig. 6, comprises a plate having two concentric rows of radial slots l2 and i3. In slots i2 a number of keys I4, l5, l6, ll, l8, and I9 are distributed and in slots l3 a single key 20 is placed. The relative distribution of the keys M to 19 in the slots determines the relative lengths of succeeding signal periods.

A plate 2i mounted in front of the dial H is provided with a hole 22 through which the setting of key 20 may be viewed. This plate is of such diameter that it partially covers the ends of the keys l4 to 20 and thereby locks the keys into their respective slots. The uncovered portions of these keys then still indicate the relative positions of the keys in the slots. The plate may be removed, when a setting is to be changed by removing a screw 29 in the center of the plate. The key 20 is used to change the relation of the controller operation to the operation of other controllers in the system so as to obtain a desired progression of certain signal periods such as the main street go period for example. .It is therefore referred to as the progression adjusting key. Keys I4 to l8 are spaced from each other in the slots !2 in accordance with any desired cyclepercentage allotted to each signal in the signaling cycle-and the key I9 is used to maintain synchronism between the dial and the signal circuit control drum.

The panel 9 is also provided with three switches 23, 24 and 25 which are connected respectively to shut off the signals; to switch from automatic to manual control, or vice versa; and to temporarily stop the timer in order to re-synchronize it with other timers in a non-interconnected system. The operation of these switches and of the keys I4 to 20 will be further explained in connection with the circuit diagram, Fig. 6.

In Fig. 2 I have illustrated in perspective the mechanism of the timer. The dial 1 I is mounted on a shaft 26 which does not appear in this figure but is shown in Fig. 6. This shaft is, in turn, mounted in a bearing in a spider 21. The spider 2! is integral with the panel 9 and is spaced from the panel sufficiently to provide room for the dial ll to move in the panel-concentric with the opening Ill therein. A gear 28 is mounted on the shaft 26 on the outside of the spider 21.

' This gear may be removed and other gears having a greater or smaller number of teeth may be substituted. A motor 30. provided with a shaft 3| and a pinion 32 is mounted on a plate 33, The motor shaft and pinion do not appear in Fig. 2 but are illustrated in Fig. 6. The plate 33 is provided with a pivot arm 34 at its upper end and is thereby pivoted on a bolt 35 mounted in the spider 21. The plate 33 may be adjusted about its pivot and held in the selected positions by a bolt 36 mounted in the end of a stud 31 projecting from the back of the panel 9. The edge of the plate 33 is clamped between the end of the stud and the head of the bolt. When it is desired to change the transmission ratio between the dial and the motor, the bolt 36 is loosened, thereby permitting the plate 33 to swing about its pivot. A new gear may then be placed on the shaft 26 and the plate then moved about its pivot until this new gearand the motor pinion engage. It is then only necessary to tighten the bolt 36 and the timer is again ready for operation at the new rate of speed which determines a new cycle length.

In order to obtain a clear indication of the cycle length which is in use, a pointer 38 is attached to the lower end of the plate 33- and is projected through an opening 39 provided therefor in the panel at theedge ofopening Ill. Pointer 38 changes-its position whenever a new gear is placed on the dial shaft 25 and by placing proper markings, as indicated in Fig. 1, underneath the opening 39, the cycle lengths corresponding to the respective gear sizes may be indicated.

In an insulating block 40, see Fig. 2, mounted on the back of the panel 9, above the dial ll, three pairs of contacts are mounted in cooperative relation with the keys in the rotating dial. These contacts control circuits which will be described in connectionwith the circuit diagram Fig. 6.

Below the spider 2i and dial assembly a signal circuit controller comprising a cam shaft ii, a contactblock t2 and a series of contacts are mounted in operating relation to the cams on the cam shaft iii. The cam shaft is mounted horizontally in bearings mounted in ribs 63 projecting from the back of the panel and the block 52 is mounted on the back of panel 9 by means of screws 56 shown in Fig. l. The block is mounted above an opening 57 in a base plate 86 projecting from the back of the panel and reinforced by the ribs 58 which support the shaft bearing. An operating coil 35 provided with a rectangular laminated core dB is pivotally suspended from a lug 37 on the panel. The core dB is provided with a movable center leg or plunger 38 which is connected through a pawl and ratchet device to rotate the shaft ii step-by-step responsive to each energization of the coil 15.

The center leg 48 is connected to a pawl crank 69 which is pivoted to the cam shaft li and carries a pawl at its free end. The pawl is mounted on a shaft 5| projecting through the free end of the crank 49 and through the core leg i8. A spring 52 is connected at one end to a lug on the crank 39 and to alug on the pawl shaft 5!. It is maintained under tension to hold the pawl 50 in engagement with a ratchet wheel 53. When the coil s5 is energized the pawl 51] rides over a tooth of the ratchet wheel 53 which is rigidly mounted on the shaft H and when the coil 45 is de-energized the core leg Q8 falls, the pawl catches a tooth of the wheel 53 and advances it, and the shaft ti, one step. A spring 55 prevents a clockwise rotation of the cam shaft and a spring 54 aids the spring 52 in holding the.

pawl 50 in its notch to prevent a movement of the shaft 6| beyond the position to which it is moved by the pawl 50.

In Figs.- 3 and 4 I have illustrated an improved controller drum. For the control of traffic signalsit is desirable to provide a simple inexpensive and flexible drum, or cam set, which may be manufactured in quantities and may be readily arranged to provide the control for any one of the numerous signaling cycles required at different intersections. To provide such simplicity ind flexibility I provide a cam 59 comprising a disk' made of insulating material having a square hole through its center so that it may be turned by a similarly square shaft. The disk is provided with a wide rim, a hub and a web portion between this rim and the hub. Radial slots divide the rim and web into sectors, any one or any number of which may be readily broken off.

In Fig. 4, I have illustrated an improved cam built in accordance with my invention. The cam comprises a circular disk of insulating material provided with a hub 60 which is made wider than the rim, to provide for spacing of the disks, through which a square hole 6| extends. The rim 62 is supported by the web section 63. Slots 66 extending radially from the hub through the rim divide the rim 62 and the web' 63 into several sectors. In the example illustrated, the cam is provided with six sectors. This number of sectors is suitable for the most common traffic signal cycle. Any other number of sectors may, of course, be used. The disk being made of a frangible inolded insulating compound, such as a phenolic condensation product and a suitable filler, or equivalent compound, it is easy to break off a sector of the rim between two radial slots, as shown in Fig. 4. With a supply of these disks it is, therefore, possible to assemble a drum, as

disclosed in Fig. 3. In this figure the ratchet wheel 53 is attached to the shaft in some convenient manner as by a set screw 65. A group of disks 59 are then placed on the shaft with their respective slots correspondingly arranged. A

collar 66 is then placed on theshaft and fasaway in each position of the drum to permit the necessary contacts to close. The drum is operated through six positions. When the contact-carrying arms ride on the rim of their respective cams the circuits controlled by the respective cams are open and where a section of the rim is broken away the corresponding contacts and circuit are closed. It is, therefore, only necessary to determine the circuits that are to be closed in each position of the controller and break away that section of the rim in the corresponding cams. If later it is desired to change this operating cycle it is only necessary to slip new disks on to the shaft, in place of the old ones.

In -Fig. 5, I have illustrated a section of the contact block 412 having one pair of contacts assembled thereon and another set disassembled to illustrate clearly the cooperating elements thereof. The contact block 32 is provided with two rows of contacts 78 and ll. The cont-acts it are connected'to a source of current and the contacts H are the terminals of signal circuits. The contacts ii are each provided with a terminal strip 68 and a screw 69, or any other suitable means, by means of which conductors lead ing to the signals may be attached. A metal strip, or contact arm, 12 bridges each pair of the terminals in the two rows iii and ii. Each strip carries a pair of contacts 73 and i6 engaging respectively a contact ill and a contact H.

Each strip i2 is provided with a hole 75- through which a pin 18 is projected. The pin 76 is provided with a head I1 and an ear 118. The car '78 is at the lower end of the pin and is braced against the underside of the block after being inthat the ear -I8 catches the underside of the block. One end of the strip 12 projects beyond .the edge of the contact block 42 and the block is placed in such relation to the cam shaft that this strip end rides on the perimeter of the cam on the drum controller. When the end of a strip rides on a rim 62, the contact I3 on that strip is lifted off its cooperating contact I and the corresponding circuit is open, but when a section of the rim is broken away the strip I2 drops to .close that cir- 'cuit. Spacing lugs 8| on the block 42 maintain a proper alinement and Spacing between the contact arms 61.

In Fig. 6, I have illustrated a schematic wiring diagram of the above-described traiiic signal tim er. The motor generally designated by the numeral 30 is actually a double motor provided with a single shaft 3|. The armatures and speedreducing gears are enclosed in a casing 85 and the two fields, 86 and 81, are diagrammatically shown. This motor is preferably a self-starting synchronous motor of the type disclosed in U. S. Patent 1,430,867. When both fields 86 and 81 are energized they tend to rotate the motor shaft in opposite directions and since the forces exerted are equal, the shaft remains stationary. The keys I4 to 20, inserted in the slots I2 and I3 of dial II, actuate .the movable contacts for three separate circuits, which control the operation of this motor.

The contacts mounted in the insulating block 40, Fig. 2, are placed side by side and are actuated by predetermined ones of the keys in the rotating dial. Thus a movable contact 89 is mounted on a resilient arm 90. This spring arm is mounted rigidly, at one end, in the block 40 and is provided with an actuating (insulation) block 9I at its forward end. When the dial II is moved by the motor 30, keys I4 and I8 engage the block 9| to intermittently move the contact 89 into engagement with a stationary contact 92. This intermittent closure causes an intermittent energlzation of the coil 45 and, therefore, a step-by-step operation of the signal circuit drum.

A second movable contact 93 mounted on a resilient arm 94 is actuated by the key I9. This key is longer than the keys I4 to I8 and is notched out so that it does not engage the block 9i and thereby actuate the contact 89. An insulation block 95 is mounted on the end of the resilient arm 94 and when the key I9 passes under it the contact 93 is raised into engagement with a contact 96 to close a shunt circuit around a break in the drum operating circuit. The closing of this circuit energizes the drum advance magnet and moves the drum so that the break in its circuit is closed and it may again be moved by operation of the keys I4 to I8. In this manner, synchronism is maintained between the dial and the signal drum.

A third circuit is operated by the key 20. This key is placed into one of the slots I3 and engages an insulation block 91 attached to the free end of a resilient arm 98 to raise a contact 99 attached to the arm into engagement with a stationary contact I00. This stationary contact I00, as well as the stationary contacts 92 and 96, are respectively mounted on resilient arms I2I which normally hold the contacts in a predetermined position relatively to the movable contacts. The circuit closed by this last pair of cont-acts energizes the field 8'! and stops the timer before the key 20 releases block 91 to open the circuit. The timer is stopped in this manner until a master Itimer, diagrammatically indicated at IIW momentarily interrupts the source of power to the field 81 at predetermined moments at which the timer comes into synchronism with the master timer. This interruption is long enough for keys 20, in the respective timers, to pass by the blocks 91 and thereby open-the circuits to the braking fields 81 respectively. If .the controllers are in synchronism, the master controller II8 opens the current to conductor II4 just prior to or substantially simultaneouslv with the closing of the circuit .by key 20. Consequently, the controller will not be stopped.

The operation of the timer will be better understood by reference to the circuits indicated in Fig. 6. The switch 23 is used as a power switch for the traflic signals and when closed completes a circuit from a source to the conductor IN. The conductor IN is connected to the contacts I0 and thereby furnishes power to the signal lamps I02 through the cooperating contacts and cable I03. It may be noted here that the motor field 85 may be permanently energized through conductor I04 connected permanently to the source through a conductor I05 and through a conductor I06 to the field 88. The motor 30 being a synchronous motor, it may readily be maintained instep with other similar motors in the system, and when once adjusted it will keep the dial II rotating in a predetermined relation to the other dials in the system. For that reason the interconnection II4 between the controllers and the contacts 98 and 99 may be dispensed with if desired. A second switch 24 is operable between two positions and may connect the actuating coil 45 through a conductor I01 to a manually operated switch I08. When this connection is made power may be applied manually to the coil 45 from a source through conductors I05, swit'ch I08, conductor I09, switch 24, conductor I01, coil 45 and ground. When this switch 24 is thrown to its second position it places the coil under control of the dial by establishing a circuit from conductor I05, conductor I04, to the resilient contact arm 90 through conductor IIO to a set of contacts I0 to I4 operated by a cam 59, conductors I I I and H2 to the switch 24.

With this arrangement, the cam 59 maintains the circuit between conductors H0 and III closed during all positions of the controller except one. At this one position the circuit is broken and may not-be closed until a shunt circuit operated by contacts 93 and 96 is closed through the actuation of the key I9. In other words, this comprises the interlock between the dial and the drum, and the drum cannot be advanced beyond that position by any key but key I9. The shunt circuit through which the coils 45 are energized when the circuit between contactors H0 and III may be traced from conductor I04 to conductor II3 through the stationary contact 99, movable contact 93, contact arm 94, and conductor III.

As stated above, the key 20 operates a third pair of contacts 99 and I00 for the purpose of maintaining in synchronism this controller dial with other similar dials in the system. For this purpose an interconnecting, or common, conductor H4 is provided and connected to each controller through a conductor H5 and the above mentioned pair of contacts which are normally open. The conductor H4 is normally connected to a source of current by the master controller II8 which is provided with a switch II9 operated by a motor driven cam I20 and when the key 20 tween contacts 99 and Hill, a circuit is established to the second fleld of the motor which may be termed the braking field. This circuit may be traced from conductors i 14, H5, resilient arm 98, contacts 99, I00, conductor H6, switch 25, conductor H1, and held 81 to ground. During operation, therefore, when the key 20 arrives at the position at which it closes this circuit, the motor is stopped and, in order to restart it, -the current to conductor H4 is periodically interrupted by the cam-operated switch H9 in the master timer. The cam I20 in the master controller H8 may be driven by a motor similar to that used in the secondary timers or by any other suitable timing mechanism. This arrangement, therefore, provides a simple means for starting up all of the controllers simultaneously. For the purpose or manually stopping and resynchronizing with; other non-interconnected timers, the motor switch25 may be manually moved to a second-positionin which the field 81 is connected to a positive source of current through a conductor I22 independently of the above-described circuit.

The arrangement of the three sets of contacts 89-92, 93-96, and 99-!00 side by side within the block 40 and the actuating blocks 9|, 95, and

91 therefore being in an established relationship,

the dial is entirely independent of the contact mechanism and the operating relationship between the dial and the several pairs of contacts is entirely dependent upon the spacing of the keys relatively to each other within the dial.

The signals I02 are the commonly used signals comprising a lamp having a colored lens mounted before it. The lenses commonly used are (R) red, (A)-amber and (G) green. Two similar'sets are used for each of the intersecting streets. The cable I03 leading to these lamps is connected to the circuit controlling contacts in such manner that the proper lamps will be energized at each of the six positions of the drum. One such cycle, very often used, comprises (1) Green-main street, Rcd-cross street (2) G-main, Amber-main, R-cross (3) Amberboth streets (4) Rmain Gcross (5) Rr-D'XBJD Gcross, Across (6) Amber both streets.

What I claim as new and desire to secure by Letters Patent of the United States is:

, 2,236,297 engages the block 91 so asv to close the circuit bel. A cam for a drum controller comprising a disk of frangible insulating material including a hub, a rim having a width less than said hub, a

- web portion which is narrower than said rirr section between said hub and said rim, and slots extending through said rim portion into said web portion whereby said rim is divided into sections and said sections are solely supported by said web section.

2. A cam for a drum controller comprising a disk of frangible insulating material, said disk including a hub having an irregular hole therethrough for positioning said hub upon a shaft, a rim section narrower than said hub and a web between said rim and said hub, said web being narrower than said rim and radial slots projecting through said rim portion and dividing said rim into sections having a predetermined relation to said positioning hole in said hub whereby upon assembling a group of said disks upon a shaft the rim of said disks are spaced from each other and said rim sections may be respectively removed to form a cam surface of predetermined relationship relative to said hub.

3. A drum for a controller comprising a shaft, a series of disks mounted adjacent each other upon said shaft, said disks being made of frangible insulating material and being provided with a hub, a rim, and a web between said hub and rim, radial slots extending through said rim dividing said rim into sections each of which is respectively supported by a web portion, said hub being wider than said rim whereby the rims of said disks are spaced from each other and any desired rim section may be readily broken ofl at the web section.

4. A drum for a controller comprising a shaft, and a series of disks of frangible material each having a hub, a rim, and a web of less thickness than the hub and rim connecting the hub to the rim, said disks being arranged on said shaft with the rims in spaced relation to each other, said disks being provided with circumferentially spaced radial slots which extend through the rims into the webs dividing said rims into sections each of which is supported by a web portion, whereby after the disks are assembled on the shaft any desired rim section may be readily broken ofi at the web section.

. RALPH A. REID.

CERTIFICATE OF CORRECTION. Patent No. 2,256,297. a March 2 19in.

RALPH A. REID.

It is hereby certified that error appears in the printed specification 3f the above. nnmbered patent requiring correction as follows: Page 5, first column, line 59, for "and" read to-; line to, for to'f read --and-;

page 1;, second column, line 21, claim 2, for the word "rim" read --ri.ms-'-;

and that the said Letters Patent should be read with this correction therein tl'mt the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of May, A. D. 191 1 Henry Van Arsdale (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,256,297. March 2 191m.

RALPH A. REID. It is hereby certified that error appears in the printed specificatior of the above. mimbered patent requiring correction as f0 llows: Page 5, firsi column, line 59, for "and" read to; line 1 0, for to" read --and--;

page 14., second column, line 21, claim 2, for the word "rim" read --rims'-;

and that the said Letters Patent should be read with this correction therei:

tl'nt the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of May, A. D. 191;]

Henry Van Ar sdale (Seal) Acting Commissioner of Patents 

